Endocrine system: Glands/hormones

• The endocrine system is one of the body's major info systems that instructs glands to release hormones directly into the bloodstream, which are then carried towards target organs in the body. It Regulates bodily functions, growth and psychological factors.
• The gland is an organ that synthesises substances such as hormones (neurotransmitters in the brain).
• Hormones are chemical substances that circulate in the bloodstream and only affect target organs.
• Fight or flight response is the way that an animal responds when stressed. The body becomes psychologically aroused in readiness to fight an aggression or flee.
• Adrenaline is a hormone produced by the adrenal glands, which is part of the body's immediate stress response system. It has a strong effect on the cardiovascular system (stimulating the HR, contracting blood vessels and dilating air passages).
• Pituitary gland (master gland) - secretes many different hormones, some affecting other glands
• ES works alongside the nervous system to control vital functions in the body, but acts more slowly than NS. Although, it does have more widespread and powerful effects than the NS.
• Thyroid gland (neck) - Regulates metabolism and affects cells in the heart, increasing HR, releasing thyroxine. This then affects growth
• Pancreas (just behind stomach) - Regulates levels of sugar in the blood releasing insulin and glucagon
• Pineal gland - modulates sleep patterns keeping the body to the circadian rhythm, secreting melatonin
• Ovaries are secondary sexual characteristics in females, appearing at puberty, release oestrogen (reproductive gland)
• Testicle develops secondary sexual characteristics in males, appears at puberty, releases testosterone (reproductive gland)
• Hypothalamus is positioned just next to the pituitary gland. This links the Nervous system to the Endocrine system, working with pituitary. Maintains homeostasis of bodily systems.  Example of hormone: corticotropin-releasing hormone (CRH) detected by pituitary gland in fight or flight response.
• The Endocrine system (ES) and Autonomic Nervous system (ANS) can work together:

  • When something perceived as stressful, ANS changes from resting state (parasympathetic) to psych aroused state (sympathetic)
  • Pituitary gland releases adrenocorticotrophic hormone (ACTH)
  • ACTH affects cells of adrenal gland to release adrenaline in bloodstream
  • Adrenaline triggers psych changes in body e.g. Increased HR which creates psych arousal needed for fight/flight response.
• Parasympathetic divisions are antagonistic to sympathetic divisions. (work in opposition to each other)